A magnetic disk drive is a digital data storage device that stores digital data on magnetic medium known as a disk. The disk, in general, comprises a plurality of tracks for storing the digital data. Data is stored on the tracks of the disk in the form of magnetic polarity transitions induced into a magnetic layer covering the disk.
During operation of the disk drive, the disk is rotated about an axis by a spin motor at a substantially constant angular speed. To perform a transfer of data with the disk, a transducer, known as a recording head, is centered above a track of the rotating disk. Once centered, the head can be used to transfer data to the track (during a write operation) or to transfer data from the track (during a read operation). During writing, for example, a write current is delivered to the centered head to create an alternating magnetic field in a lower portion of the head that induces magnetic polarity transitions onto the track. During reading, the centered head senses magnetic fields emanating from the magnetic polarity transitions on the moving track to create an analog read signal representative of the data thereon.
The recording head may be a dual element head having a read element for performing a read operation and a write element for performing a write operation. It is known to make the read element wider than the write element provided that the write element contains erase bands on its edges to “erase” old data from a track on the disk and thereby prevent the read element from sensing that old data. This configuration is described in U.S. Pat. No. 5,940,250 (McNeil et al.), the contents of which are hereby incorporated by reference into this application as if set forth herein in full.